refactor: move to [observer](https://bevyengine.org/examples/ecs-entity-component-system/observers/) based systems

Cargo.lock

@@ -3083,7 +3083,7 @@ dependencies = [
 
 [[package]]
 name = "maze-ascension"
-version = "0.2.0"
+version = "0.2.2"
 dependencies = [
  "anyhow",
  "bevy",

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "maze-ascension"
 authors = ["Kristofers Solo <dev@kristofers.xyz>"]
-version = "0.2.0"
+version = "0.2.2"
 edition = "2021"
 
 [dependencies]

src/dev_tools/ui/maze_controls.rs

@@ -1,7 +1,7 @@
 use crate::{
     floor::components::{CurrentFloor, Floor},
-    maze::{components::MazeConfig, events::MazeEvent, GlobalMazeConfig, MazePluginLoaded},
-    player::events::PlayerEvent,
+    maze::{components::MazeConfig, events::RespawnMaze, GlobalMazeConfig, MazePluginLoaded},
+    player::events::RespawnPlayer,
 };
 use bevy::{prelude::*, window::PrimaryWindow};
 use bevy_egui::{
@@ -58,16 +58,11 @@ pub(crate) fn maze_controls_ui(world: &mut World) {
             // Handle updates
             if changed {
                 maze_config.update(&global_config);
-
-                if let Some(mut event_writer) = world.get_resource_mut::<Events<MazeEvent>>() {
-                    event_writer.send(MazeEvent::Recreate {
-                        floor: floor_value,
-                        config: maze_config,
-                    });
-                }
-                if let Some(mut event_writer) = world.get_resource_mut::<Events<PlayerEvent>>() {
-                    event_writer.send(PlayerEvent::Respawn);
-                }
+                world.trigger(RespawnMaze {
+                    floor: floor_value,
+                    config: maze_config,
+                });
+                world.trigger(RespawnPlayer);
             }
         }
     });

src/floor/events.rs

@@ -0,0 +1,20 @@
+use bevy::prelude::*;
+
+use crate::maze::components::MazeConfig;
+
+#[derive(Debug, Reflect, Event)]
+pub struct SpawnFloor {
+    pub floor: u8,
+    pub config: MazeConfig,
+}
+
+#[derive(Debug, Reflect, Event)]
+pub struct RespawnFloor {
+    pub floor: u8,
+    pub config: MazeConfig,
+}
+
+#[derive(Debug, Reflect, Event)]
+pub struct DespawnFloor {
+    pub floor: u8,
+}

src/floor/mod.rs

@@ -1,6 +1,7 @@
 pub mod components;
+pub mod events;
 mod systems;
 
 use bevy::prelude::*;
 
-pub(super) fn plugin(app: &mut App) {}
+pub(super) fn plugin(_app: &mut App) {}

src/floor/systems/mod.rs

@@ -1 +1 @@
-mod spawn;
+

src/lib.rs

@@ -62,6 +62,7 @@ impl Plugin for AppPlugin {
             screens::plugin,
             theme::plugin,
             maze::plugin,
+            floor::plugin,
             player::plugin,
         ));
 

src/maze/events.rs

@@ -2,9 +2,19 @@ use bevy::prelude::*;
 
 use super::components::MazeConfig;
 
-#[derive(Debug, Event)]
-pub enum MazeEvent {
-    Create { floor: u8, config: MazeConfig },
-    Recreate { floor: u8, config: MazeConfig },
-    Remove { floor: u8 },
+#[derive(Debug, Reflect, Event)]
+pub struct SpawnMaze {
+    pub floor: u8,
+    pub config: MazeConfig,
+}
+
+#[derive(Debug, Reflect, Event)]
+pub struct RespawnMaze {
+    pub floor: u8,
+    pub config: MazeConfig,
+}
+
+#[derive(Debug, Reflect, Event)]
+pub struct DespawnMaze {
+    pub floor: u8,
 }

src/maze/mod.rs

@@ -4,17 +4,20 @@ pub mod errors;
 pub mod events;
 pub mod resources;
 mod systems;
+mod triggers;
 
 use bevy::{ecs::system::RunSystemOnce, prelude::*};
 use components::Maze;
-use events::MazeEvent;
+use events::{DespawnMaze, RespawnMaze, SpawnMaze};
 pub use resources::{GlobalMazeConfig, MazePluginLoaded};
 
 pub(super) fn plugin(app: &mut App) {
     app.init_resource::<GlobalMazeConfig>()
-        .add_event::<MazeEvent>()
+        .add_event::<SpawnMaze>()
+        .add_event::<RespawnMaze>()
+        .add_event::<DespawnMaze>()
         .register_type::<Maze>()
-        .add_plugins(systems::plugin);
+        .add_plugins((systems::plugin, triggers::plugin));
 }
 
 pub fn spawn_level_command(world: &mut World) {

src/maze/systems/event_handler.rs

@@ -1,54 +0,0 @@
-use super::{spawn::spawn_floor, update::update_floor};
-use crate::{
-    floor::components::Floor,
-    maze::{components::Maze, events::MazeEvent, GlobalMazeConfig},
-};
-use bevy::prelude::*;
-
-pub(crate) fn handle_maze_events(
-    mut commands: Commands,
-    mut meshes: ResMut<Assets<Mesh>>,
-    mut materials: ResMut<Assets<StandardMaterial>>,
-    mut event_reader: EventReader<MazeEvent>,
-    mut maze_query: Query<(Entity, &Floor, &mut Maze)>,
-    global_config: Res<GlobalMazeConfig>,
-) {
-    for event in event_reader.read() {
-        match event {
-            MazeEvent::Create { floor, config } => {
-                if maze_query.iter().any(|(_, f, _)| f.0 == *floor) {
-                    warn!("Floor {} already exists, skipping creation", floor);
-                    continue;
-                }
-                spawn_floor(
-                    &mut commands,
-                    &mut meshes,
-                    &mut materials,
-                    *floor,
-                    config,
-                    &global_config,
-                );
-            }
-            MazeEvent::Recreate { floor, config } => {
-                let result = update_floor(
-                    &mut commands,
-                    &mut meshes,
-                    &mut materials,
-                    &mut maze_query,
-                    *floor,
-                    config,
-                    &global_config,
-                );
-                if let Err(e) = result {
-                    warn!("Failed to update floor {}: {}", floor, e);
-                }
-            }
-            MazeEvent::Remove { floor } => {
-                match maze_query.iter().find(|(_, f, _)| f.0 == *floor) {
-                    Some((entity, _, _)) => commands.entity(entity).despawn_recursive(),
-                    _ => warn!("Floor {} not found for removal", floor),
-                }
-            }
-        }
-    }
-}

src/maze/systems/mod.rs

@@ -1,12 +1,5 @@
-pub mod common;
-pub mod event_handler;
 pub mod setup;
-pub mod spawn;
-pub mod update;
 
 use bevy::prelude::*;
-use event_handler::handle_maze_events;
 
-pub(super) fn plugin(app: &mut App) {
-    app.add_systems(Update, handle_maze_events);
-}
+pub(super) fn plugin(_app: &mut App) {}

src/maze/systems/setup.rs

@@ -1,7 +1,7 @@
-use crate::maze::{components::MazeConfig, events::MazeEvent};
+use crate::maze::{components::MazeConfig, events::SpawnMaze};
 use bevy::prelude::*;
 
-pub(crate) fn setup(mut event_writer: EventWriter<MazeEvent>) {
+pub(crate) fn setup(mut commands: Commands) {
     let config = MazeConfig::default();
-    event_writer.send(MazeEvent::Create { floor: 1, config });
+    commands.trigger(SpawnMaze { floor: 1, config });
 }

src/maze/systems/update.rs

@@ -1,43 +0,0 @@
-use super::{common::generate_maze, spawn::spawn_maze_tiles};
-use crate::{
-    floor::components::Floor,
-    maze::{
-        assets::MazeAssets,
-        components::{Maze, MazeConfig},
-        errors::{MazeError, MazeResult},
-        GlobalMazeConfig,
-    },
-};
-use bevy::prelude::*;
-
-pub(super) fn update_floor(
-    commands: &mut Commands,
-    meshes: &mut ResMut<Assets<Mesh>>,
-    materials: &mut ResMut<Assets<StandardMaterial>>,
-    maze_query: &mut Query<(Entity, &Floor, &mut Maze)>,
-    floor: u8,
-    maze_config: &MazeConfig,
-    global_config: &GlobalMazeConfig,
-) -> MazeResult<()> {
-    let (entity, _, mut maze) = maze_query
-        .iter_mut()
-        .find(|(_, f, _)| f.0 == floor)
-        .ok_or(MazeError::FloorNotFound(floor))?;
-
-    maze.0 = generate_maze(maze_config)?;
-
-    commands.entity(entity).despawn_descendants();
-    let assets = MazeAssets::new(meshes, materials, global_config);
-    spawn_maze_tiles(
-        commands,
-        entity,
-        &maze.0,
-        &assets,
-        maze_config,
-        global_config,
-    );
-
-    commands.entity(entity).insert(maze_config.clone());
-
-    Ok(())
-}

src/maze/triggers/common.rs

@@ -4,7 +4,7 @@ use crate::maze::{
 };
 use hexlab::{GeneratorType, HexMaze, MazeBuilder};
 
-pub(super) fn generate_maze(config: &MazeConfig) -> MazeResult<HexMaze> {
+pub(crate) fn generate_maze(config: &MazeConfig) -> MazeResult<HexMaze> {
     MazeBuilder::new()
         .with_radius(config.radius)
         .with_seed(config.seed)

src/maze/triggers/despawn.rs

@@ -0,0 +1,14 @@
+use crate::{floor::components::Floor, maze::events::DespawnMaze};
+use bevy::prelude::*;
+
+pub(super) fn despawn_maze(
+    trigger: Trigger<DespawnMaze>,
+    mut commands: Commands,
+    query: Query<(Entity, &Floor)>,
+) {
+    let DespawnMaze { floor } = trigger.event();
+    match query.iter().find(|(_, f)| f.0 == *floor) {
+        Some((entity, _)) => commands.entity(entity).despawn_recursive(),
+        _ => warn!("Floor {} not found for removal", floor),
+    }
+}

src/maze/triggers/mod.rs

@@ -0,0 +1,15 @@
+pub mod common;
+mod despawn;
+mod respawn;
+mod spawn;
+
+use bevy::prelude::*;
+use despawn::despawn_maze;
+use respawn::respawn_maze;
+use spawn::spawn_maze;
+
+pub(super) fn plugin(app: &mut App) {
+    app.add_observer(spawn_maze)
+        .add_observer(respawn_maze)
+        .add_observer(despawn_maze);
+}

src/maze/triggers/respawn.rs

@@ -0,0 +1,53 @@
+use super::{common::generate_maze, spawn::spawn_maze_tiles};
+use crate::{
+    floor::components::Floor,
+    maze::{
+        assets::MazeAssets, components::Maze, errors::MazeError, events::RespawnMaze,
+        GlobalMazeConfig,
+    },
+};
+use bevy::prelude::*;
+
+pub(super) fn respawn_maze(
+    trigger: Trigger<RespawnMaze>,
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+    mut maze_query: Query<(Entity, &Floor, &mut Maze)>,
+    global_config: Res<GlobalMazeConfig>,
+) {
+    let RespawnMaze { floor, config } = trigger.event();
+
+    let (entity, _, mut maze) = match maze_query
+        .iter_mut()
+        .find(|(_, f, _)| f.0 == *floor)
+        .ok_or(MazeError::FloorNotFound(*floor))
+    {
+        Ok((entity, floor, maze)) => (entity, floor, maze),
+        Err(e) => {
+            warn!("Failed to update floor ({floor}). {e}");
+            return;
+        }
+    };
+
+    maze.0 = match generate_maze(config) {
+        Ok(generated_maze) => generated_maze,
+        Err(e) => {
+            warn!("Failed to update floor ({floor}). {e}");
+            return;
+        }
+    };
+
+    commands.entity(entity).despawn_descendants();
+    let assets = MazeAssets::new(&mut meshes, &mut materials, &global_config);
+    spawn_maze_tiles(
+        &mut commands,
+        entity,
+        &maze.0,
+        &assets,
+        config,
+        &global_config,
+    );
+
+    commands.entity(entity).insert(config.clone());
+}

src/maze/triggers/spawn.rs

@@ -3,6 +3,7 @@ use crate::{
     maze::{
         assets::MazeAssets,
         components::{Maze, MazeConfig, Tile, Wall},
+        events::SpawnMaze,
         resources::GlobalMazeConfig,
     },
 };
@@ -13,30 +14,43 @@ use std::f32::consts::{FRAC_PI_2, FRAC_PI_3, FRAC_PI_6};
 
 use super::common::generate_maze;
 
-pub(super) fn spawn_floor(
-    commands: &mut Commands,
-    meshes: &mut ResMut<Assets<Mesh>>,
-    materials: &mut ResMut<Assets<StandardMaterial>>,
-    floor: u8,
-    maze_config: &MazeConfig,
-    global_config: &GlobalMazeConfig,
+pub(super) fn spawn_maze(
+    trigger: Trigger<SpawnMaze>,
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+    maze_query: Query<(Entity, &Floor, &Maze)>,
+    global_config: Res<GlobalMazeConfig>,
 ) {
-    let maze = generate_maze(maze_config).expect("Failed to generate maze during spawn");
+    let SpawnMaze { floor, config } = trigger.event();
+    if maze_query.iter().any(|(_, f, _)| f.0 == *floor) {
+        warn!("Floor {} already exists, skipping creation", floor);
+        return;
+    }
+
+    let maze = generate_maze(config).expect("Failed to generate maze during spawn");
 
     let entity = commands
         .spawn((
             Name::new(format!("Floor {}", floor)),
             Maze(maze.clone()),
-            Floor(floor),
+            Floor(*floor),
             CurrentFloor, // TODO: remove
-            maze_config.clone(),
+            config.clone(),
             Transform::from_translation(Vec3::ZERO),
             Visibility::Visible,
         ))
         .id();
 
-    let assets = MazeAssets::new(meshes, materials, global_config);
-    spawn_maze_tiles(commands, entity, &maze, &assets, maze_config, global_config);
+    let assets = MazeAssets::new(&mut meshes, &mut materials, &global_config);
+    spawn_maze_tiles(
+        &mut commands,
+        entity,
+        &maze,
+        &assets,
+        config,
+        &global_config,
+    );
 }
 
 pub(super) fn spawn_maze_tiles(

src/player/events.rs

@@ -1,8 +1,10 @@
 use bevy::prelude::*;
 
 #[derive(Debug, Event)]
-pub enum PlayerEvent {
-    Spawn,
-    Respawn,
-    Despawn,
-}
+pub struct SpawnPlayer;
+
+#[derive(Debug, Event)]
+pub struct RespawnPlayer;
+
+#[derive(Debug, Event)]
+pub struct DespawnPlayer;

src/player/mod.rs

@@ -2,15 +2,18 @@ mod assets;
 pub mod components;
 pub mod events;
 mod systems;
+mod triggers;
 
 use bevy::{ecs::system::RunSystemOnce, prelude::*};
 use components::Player;
-use events::PlayerEvent;
+use events::{DespawnPlayer, RespawnPlayer, SpawnPlayer};
 
 pub(super) fn plugin(app: &mut App) {
     app.register_type::<Player>()
-        .add_event::<PlayerEvent>()
-        .add_plugins(systems::plugin);
+        .add_event::<SpawnPlayer>()
+        .add_event::<RespawnPlayer>()
+        .add_event::<DespawnPlayer>()
+        .add_plugins((triggers::plugin, systems::plugin));
 }
 
 pub fn spawn_player_command(world: &mut World) {

src/player/systems/despawn.rs

@@ -1,9 +0,0 @@
-use bevy::prelude::*;
-
-use crate::player::components::Player;
-
-pub(super) fn despawn_players(commands: &mut Commands, query: &Query<Entity, With<Player>>) {
-    for entity in query.iter() {
-        commands.entity(entity).despawn_recursive();
-    }
-}

src/player/systems/event_handler.rs

@@ -1,53 +0,0 @@
-use crate::{
-    floor::components::CurrentFloor,
-    maze::{components::MazeConfig, GlobalMazeConfig},
-    player::{components::Player, events::PlayerEvent},
-};
-use bevy::prelude::*;
-
-use super::{despawn::despawn_players, respawn::respawn_player, spawn::spawn_player};
-
-pub(crate) fn handle_player_events(
-    mut commands: Commands,
-    mut meshes: ResMut<Assets<Mesh>>,
-    mut materials: ResMut<Assets<StandardMaterial>>,
-    mut event_reader: EventReader<PlayerEvent>,
-    maze_config_query: Query<&MazeConfig, With<CurrentFloor>>,
-    player_query: Query<Entity, With<Player>>,
-    global_config: Res<GlobalMazeConfig>,
-) {
-    for event in event_reader.read() {
-        match event {
-            PlayerEvent::Spawn => {
-                let Ok(maze_config) = maze_config_query.get_single() else {
-                    warn!(
-                        "Failed to get maze configuration for current floor - cannot spawn player"
-                    );
-                    return;
-                };
-                spawn_player(
-                    &mut commands,
-                    &mut meshes,
-                    &mut materials,
-                    maze_config,
-                    &global_config,
-                );
-            }
-            PlayerEvent::Respawn => {
-                let Ok(maze_config) = maze_config_query.get_single() else {
-                    warn!("Failed to get maze configuration for current floor - cannot respawn player");
-                    return;
-                };
-                respawn_player(
-                    &mut commands,
-                    &mut meshes,
-                    &mut materials,
-                    &player_query,
-                    maze_config,
-                    &global_config,
-                );
-            }
-            PlayerEvent::Despawn => despawn_players(&mut commands, &player_query),
-        }
-    }
-}

src/player/systems/mod.rs

@@ -1,23 +1,18 @@
-mod despawn;
-mod event_handler;
 mod input;
 mod movement;
-mod respawn;
 pub mod setup;
-mod spawn;
 
 use bevy::prelude::*;
-use event_handler::handle_player_events;
 use input::player_input;
 use movement::player_movement;
 
+use crate::maze::MazePluginLoaded;
+
 pub(super) fn plugin(app: &mut App) {
     app.add_systems(
         Update,
-        (
-            player_input,
-            player_movement.after(player_input),
-            handle_player_events,
-        ),
+        (player_input, player_movement)
+            .chain()
+            .run_if(resource_exists::<MazePluginLoaded>),
     );
 }

src/player/systems/respawn.rs

@@ -1,18 +0,0 @@
-use super::{despawn::despawn_players, spawn::spawn_player};
-use crate::{
-    maze::{components::MazeConfig, GlobalMazeConfig},
-    player::components::Player,
-};
-use bevy::prelude::*;
-
-pub(super) fn respawn_player(
-    commands: &mut Commands,
-    meshes: &mut ResMut<Assets<Mesh>>,
-    materials: &mut ResMut<Assets<StandardMaterial>>,
-    query: &Query<Entity, With<Player>>,
-    maze_config: &MazeConfig,
-    global_config: &GlobalMazeConfig,
-) {
-    despawn_players(commands, query);
-    spawn_player(commands, meshes, materials, maze_config, global_config);
-}

src/player/systems/setup.rs

@@ -1,6 +1,6 @@
-use crate::player::events::PlayerEvent;
+use crate::player::events::SpawnPlayer;
 use bevy::prelude::*;
 
-pub(crate) fn setup(mut event_writer: EventWriter<PlayerEvent>) {
-    event_writer.send(PlayerEvent::Spawn);
+pub(crate) fn setup(mut commands: Commands) {
+    commands.trigger(SpawnPlayer);
 }

src/player/triggers/despawn.rs

@@ -0,0 +1,12 @@
+use crate::player::{components::Player, events::DespawnPlayer};
+use bevy::prelude::*;
+
+pub(super) fn despawn_players(
+    _trigger: Trigger<DespawnPlayer>,
+    mut commands: Commands,
+    query: Query<Entity, With<Player>>,
+) {
+    for entity in query.iter() {
+        commands.entity(entity).despawn_recursive();
+    }
+}

src/player/triggers/mod.rs

@@ -0,0 +1,14 @@
+mod despawn;
+mod respawn;
+mod spawn;
+
+use bevy::prelude::*;
+use despawn::despawn_players;
+use respawn::respawn_player;
+use spawn::spawn_player;
+
+pub(super) fn plugin(app: &mut App) {
+    app.add_observer(spawn_player)
+        .add_observer(respawn_player)
+        .add_observer(despawn_players);
+}

src/player/triggers/respawn.rs

@@ -0,0 +1,7 @@
+use crate::player::events::{DespawnPlayer, RespawnPlayer, SpawnPlayer};
+use bevy::prelude::*;
+
+pub(super) fn respawn_player(_trigger: Trigger<RespawnPlayer>, mut commands: Commands) {
+    commands.trigger(DespawnPlayer);
+    commands.trigger(SpawnPlayer);
+}

src/player/triggers/spawn.rs

@@ -1,19 +1,25 @@
 use crate::{
+    floor::components::CurrentFloor,
     maze::{components::MazeConfig, GlobalMazeConfig},
     player::{
         assets::{blue_material, generate_pill_mesh},
         components::{CurrentPosition, Player},
+        events::SpawnPlayer,
     },
 };
 use bevy::prelude::*;
 
 pub(super) fn spawn_player(
-    commands: &mut Commands,
-    meshes: &mut ResMut<Assets<Mesh>>,
-    materials: &mut ResMut<Assets<StandardMaterial>>,
-    maze_config: &MazeConfig,
-    global_config: &GlobalMazeConfig,
+    _trigger: Trigger<SpawnPlayer>,
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+    maze_config_query: Query<&MazeConfig, With<CurrentFloor>>,
+    global_config: Res<GlobalMazeConfig>,
 ) {
+    let Ok(maze_config) = maze_config_query.get_single() else {
+        return;
+    };
     let player_radius = global_config.hex_size * 0.5;
     let player_height = player_radius * 3.5;
 

src/screens/gameplay.rs

@@ -9,10 +9,7 @@ use crate::{asset_tracking::LoadResource, audio::Music, screens::Screen};
 pub(super) fn plugin(app: &mut App) {
     app.add_systems(
         OnEnter(Screen::Gameplay),
-        (
-            spawn_level_command,
-            spawn_player_command.after(spawn_level_command),
-        ),
+        (spawn_level_command, spawn_player_command).chain(),
     );
 
     app.load_resource::<GameplayMusic>();